Bridge-painting apparatus and method

ABSTRACT

A bridge-painting apparatus employing an extensible scaffold means and method of folding the latter whereby the apparatus may be transported by a motor vehicle. The apparatus includes a mast or boom with means for extending the boom over the side of a bridge to be painted and means for raising and lowering it. The boom is provided with a reinforcing frame construction to which the extensible scaffold means is secured. A split collar construction permits the boom to be raised and lowered without dismantling any of the apparatus whereby the apparatus may be ready for operation and/or removal in an extremely short period of time. A remote control means is provided whereby the apparatus may be extended or collapsed with great facility. The vehicle on which the apparatus is mounted is provided with abutment or curbsensing means whereby the vehicle may be driven remotely and automatically.

United States Patent inventor Lewis L. Lindsay, Jr.

Richmond, Va.

Appl. No. 881,426

Filed Dec. 2, 1969 Patented Sept. 28, 1971 Assignee Bridge Painting, Inc.

Richmond, Va.

BRIDGE-PAINTING APPARATUS AND METHOD 28 Claims, 18 Drawing Figs.

US. Cl 182/14, 182/16,182/63,182/148 Int. Cl. E04g 1/24, E04g 1/36 Field oiSearch 182/13, 12, 14,16, 141,148,145, 63, 37,2, 36; 173/28 References Cited UNITED STATES PATENTS 2,121,480 6/1938 Finn 173/28 2,598,730 6/1952 Thompson 182/145 2/1954 Kaufman 2/1963 Goodell 182/36 3,357,517 12/1967 Wagner... 182/2 3,400,771 9/1968 Dorn 173/28 FOREIGN PATENTS 1,216,914 5/1966 Germany 182/145 Primary ExaminerReinaldo P. Machado Attorney-Low and Matthews I ABSTRACT: A bridge-painting apparatus employing an extensible scaffold means and method of folding the latter whereby the apparatus may be transported by a motor vehicle. The apparatus includes a mast or boom with means for extending the boom over the side of a bridge to be painted and means for raising and lowering it. The boom is provided with a reinforcing frame construction to which the extensible scaffold means is secured. A split collar construction permits the boom to be raised and lowered without dismantling any of the apparatus whereby the apparatus may be ready for operation and/or removal in an extremely short period of time. A remote control means is provided whereby the apparatus may be extended or collapsed with great facility. The vehicle on which the apparatus is mounted is provided with abutment or curbsensing means whereby the vehicle may be driven remotely and automatically.

PMENTEU SEPE 8 WI SHEET 1 UF 8 m L W ATTORNEYS PATENTEU SEP28 an 3 608 669 sum 2 OF 8 INVENTOR Lew/s L. L/ndsandr.

BY iv/W ATTORNEYS PATENTED SEP28 lQii SHEET 5 BF 8 Auxiliary Tronsmission Hydraulic Motor Hydraulic Pump Transmission Air Compressor 1 Remote Control ig. l3

INVENTOR Lew/sv L Lindsay, Jz

ATTORNEYS PATENTEMeraam SHEET 6 0F 8 INVBNTOR Lewis L. Lindsay, dz

ATTORNEYS PATENTED SEP2 819m SHEET 7 UF 8 INVENT OR.

' Lew/s L. Lindsay, Jr.

it TTORNEYS PATENTED SEP28l97| 3508.669

' sum 8 or 8 I i g 126 12s H I62 Fig. 17

INVENTOR L em's L. Lindsay, Jr.

ATTORNEYS BRIDGE-PAINTING APPARATUS AND METHOD by employing a scaffolding system which uses cables to suspend individual boards or scaffolds and which of necessity required an extensive amount of setup time as well as unduly long times to effect movement thereof from one position to another across the span of the bridge. Because of the variations in bridges in terms of length, width, height and curvature, these systems have necessarily required certain changes and modifications in their deployment from one bridge to another and have been lacking in safety.

The present invention overcomes the foregoing disadvantages and shortcomings in providing a bridge-painting apparatus which not only has built-in safety features by virtue of a rugged design, but also provides significant economic advantages in providing a system which can be moved as a selfcontained unit from jobsite to jobsite and which can be set up for operation in an extremely short period of time, such as approximately 15 minutes. After the painting is complete, the apparatus may be readily collapsed and made ready for transport to the next jobsite again in approximately 15 minutes.

Succinctly stated, this invention provides a self-contained, collapsible, remotely controlled, articulated bridge-painting apparatus mounted on a mobile platform.

One feature which stands out in making the rapid unfolding and folding of the extensible scaffold means of this invention is a split collar construction whereby the apparatus may be collapsed without dismantling of disassembling any of the apparatus. The apparatus employs a boom which is held over a side of a bridge to be painted. The boom is held in a suitable frame mounted on a turntable which in turn is mounted for rotation on the bed of the truck or motor vehicle. The boom 1 carries a reinforcing frame which provides an adequate structure for attachment to the bottom thereof of the extensible scaffold means. The attaching means by which the reinforcing frame is secured to the boom is sufficiently thin in cross section so that when suitably aligned with the split collar construction it will pass directly through the split therein so that no dismantling or disassembly of the bridge-painting apparatus is required.

The boom-holding frame itself is extensible to a limited degree as well as being tiltable. Therefore, it is possible to vary not only the lateral spacing of the boom from the side of the bridge but also the angle that the extensible scaffold means makes with respect to the underside of the bridge to be painted.

Counterweight means are provided on one side of the turntable which supports the boom and is located on the opposite side of the turntable. Means are also provided for varying the position of the counterweight means to compensate for different positions of the boom-holding means, the boom and its reinforcing structure, and the extensible scaffold means.

In addition to bridge abutment sensing means, the apparatus is also provided with remote control means by which the extension and contraction of the extensible scaffold means in the position of the boom is controlled so that the apparatus is moved to and from a stacked position on the truck bed to a bridge-painting position in which the boom is vertically suspended over the side of the bridge to be painted and the extensible scaffold means extends beneath the bridge. The remote control means also provides a completely automatic control of the motor vehicle whereby it may be unattended during the bridge-painting operation.

While the invention is described herein in connection with bridge-painting apparatus, it is to be understood that this term and the invention are also applicable to inspection and stripping operations as well. For example, workers may stand on the extensible scaffold means to strip temporary forms from beneath the bridge in the course of its construction.

The inherent advantages and improvements of the present invention will becomemore readily apparent upon considering the following detailed description of the invention and by reference to the drawings in which: I

FIG. 1 is a side elevational view of the bridge-painting apparatus of the present invention;

2 is a rear elevational view of the apparatus as viewed from line 2-2 of FIG. 1;

FIG23 is a rear elevational view similar to FIG. 2 but showing he apparatus in a different position;

FIG. 4 is a fragmentary side elevational view of the bridgepainting apparatus in its road transport position;

FIG. 5 is a fragmentary top plan view showing a platform turning wheel at the top of the boom;

FIG. 6 is an elevational view of the bridge-painting apparatus in its road transport condition as viewed from behind the cabin from line 66 of FIG. 4;

FIG. 7 is a fragmentary top plan view showing the turning wheel rotated through FIG. 8 is a fragmentary elevational view taken in vertical cross section showing a portion of the boom;

FIG. 9 is a fragmentary elevational view as viewed from line 9-9 of FIG. 8;

FIG. 10 is a fragmentary elevational view similar to FIG. 9 but showing the boom rotated through 90 and passing through the split in the split collar construction;

FIG. 11 is a plan view, taken in horizontal cross section, along line 11-11 of FIG. 9;

FIG. 12 is a plan view, taken in horizontal cross section, along line 12-l2 of FIG. 10;

FIG. 13 is a schematic view of the bridge abutment sensing and steering device and the power train used in connection with the present invention;

FIGS. 14 and 15 are plan views schematic in nature illustrating two means for effecting extension and contraction of the extensible scaffold means;

FIG. 16 is a fragmentary plan view, schematic in nature, of the bridge abutment sensing and steering deviceused in connection with the presentinvention;

FIG. 17 is a schematic diagram of a hydraulic system used in connection with the present invention; and,-

FIG. 18 is a fragmentary view in side elevation showing another means by which the extensible scaffold means may be tilted in a vertical plane.

Referring now to FIG. 1 of the drawings, there is illustrated a motor vehicle, such as a truck, indicated generally at 20, which is in bridge-painting position on a bridge span indicated at 22. The bridge painting apparatus itself is indicated generally at 24. Bridge-painting apparatus 24 is shown to comprise a turntable 26 suitably mounted for rotation on truck bed 28. Numeral 30 indicates a pain supply tub shown in FIGS. 1, 3, 4 and 6. This tub as well as hydraulic or other means for supplying the paint through hoses and the like are considered to be conventional for purposes of this application.

Referring to FIG. 2, a boom-holding frame, indicated generally at 32, holds a mast or boom 34 over the side 35 of bridge span 22. Boom 34 carries a reinforcing frame indicated generally at 36 which is substantially triangular in plan view as seen in FIGS. 6 and 7. A thin attaching means 37 which may take the form of a stub plate member suitably secured as by welding between the triangular reinforcing frame means 36 and the boom 34. The reinforcing frame means 36 provides an adequate structure for an extensible scaffold means indicated generally at 38 in FIG. 2 to be attached to the boom and its triangular reinforcing frame. The extensible scaffold means 38 provides a platform for the workers to stand in their painting, stripping or inspection operations and comprises a main scaffold or tray 40. and one or more extensible members 42 which may be telescopically received within the tray 40. In one form of the invention two such extensible members 42 were employed with a tray 40 with the tray being 32 feet in length and each of the extensible members were 9 feet in length providing, with a slight overlap of members, a total length of 48 feet from one side.

Referring to FIGS 2 and 4, a counterweight means 44 is employed to counterbalance the weight of the extension of the extensible scaffold means 38 and the boom and its frame 36 which extend over the side of bridge 35. The counterweight means 44 comprises a counterweight 46 which is mounted on a pair of legs 48, as best seen in FIG. 6, which are pivotally secured to mounting bracket 50. A pair of hydraulic cylinders 52 each having one end secured intermediate one of the legs 48 and having the other end attached to post means 54 permit he counterweight 46 to pivot about the mounting bracket 50 between an upright position and an extended position such as is indicated in solid and phantom lines in FIG. 2.

Also attached ed to post means 54 as seen best in FIG. 3, are a pair of hydraulic cylinders 56 each having a reciprocable plunger secured to a mounting bracket 58 of a tiltable frame 60. The tiltable frame 60 is shown to comprise an upright liftable frame member 59 and to have a pivotal lever arm 61 which is pivotally secured to mounting block 63 on he rotatable turntable 26. The tiltable frame 60 has a pair of angle members 62 in order to support a telescoping frame 64 which together with two pair of converging arms 66 provide an A- frame mounted on the turntable 26. In order to reciprocate the telescoping frame 64 within the tiltable frame 60, a hydraulic cylinder 68 is provided. Thus as seen in FIG. 2, with the reciprocation of hydraulic cylinder 68, the frame 64 telescopes within tiltable frame 60. Frame 60 is relatively fixed with respect to the frame 64 which is movable upon the actuation of hydraulic cylinder 68.

Reference is now made to FIGS. 8-12, inclusive, for a discussion of a split collar construction 70 which permits the bridge-painting apparatus to be collapsed without dismantling or disassembling any of the apparatus. Thus, the split collar construction 70 is shown to comprise upper and lower split collar members 72 each of which have a split 74 with the split collar members 72 being vertically spaced by a split bearing at 76. The thin attaching means 37 for the reinforcing frame means 36 is alignable with the split 74 in the split collar members 72.

Reference to FIG. 7 shows a platform rotation wheel 80 which is rotatable by means of chain or cable means 82 which is entrained over pulleys 84 and 86, both of which are secured to the telescoping frame 64. A motor, not shown, drives shaft 86 to provide a winch for the platform rotation wheel. In addition to providing means for the alignment of the thin attaching means 37 with the splits 74 in split collars 72 in a manner described hereinafter, the ability to rotate the boom 34 and the platform afforded by extensible scaffold means 38 provides additional advantages. For example, some bridges have skewed supporting piers. To compensate for this, it is desirable to effect rotation of the extensible scaffold means 38 whereby the platform afforded thereby may be rotated in a horizontal plane so as to be parallel with an imaginary line drawn between he skewed supporting piers.

In the position shown in FIG. 9, the thin attaching means 37 for the reinforcing frame means 36 is substantially 90 removed from the split 74 in the split collar members 72. By rotating he platform rotation wheel 80 with cable or chain means 82 the boom 34 and its associated frame means 36 are rotated through 90 whereby the thin attaching means 37 is aligned with the split 74 in each split collar 72 whereby the boom may be elevated such as by cable means 89 in FIG. 2 vertically upwardly or downwardly as indicated by the arrows in FIG. whereby the thin attaching means 37 pass through the split 74 in the split collar members 72. Thus it is possible to elevate the boom 34 and its associated reinforcing frame 36 to the position shown in FIG. 4, in which position the boom may be folded forwardly by pivoting it about a knuckle joint 100 in boom 34. Any suitable means, such as cable means indicated generally at 89 (FIG. 2) driven by motor means M, designated by numeral 85, may be used to raise and lower boom 34.

FIGS. 14 and schematically represent the manner in which extensible platform members 42 and 420 may be telescoped within the main scaffold or tray 40. In this instance,

the extensible scaffold means 38 is shown to comprise a main scaffold or tray 40, a first extensible platform member 42 and a second extensible platform member 42a which is telescopically received within member 42. FIG. 14 shows the contraction of the extensible members wherein a cable 87 is pulled to the right over pulley 88 attached centrally of the extensible platform member 42, thence around pulley 90, attached to the extensible platform member 42 at its leftmost end then over pulley 92, and then wound around a clockwise rotating drum 94. Suitable stops, not shown, are employed to limit the movement of one individual member before the next member in the telescoping series begins to move.

In FIG. 15, a cable 87a pulls out the telescoping members sequentially by being pulled around a pulley 90a attached to extensible member 42, then around a pulley 96 located on the right end of extensible platform member 42 then around pulley 98 located on the lower left end of tray 40, and then around drum 94 which in this instance rotates counterclockwise. Again, suitable stops, not shown, are used to limit the sequential extension of the members.

As shown best in FIG. 4, the boom 34 is provided with a knuckle joint 100 by means of which the boom 34 together with its reinforcing framemeans 36 may be folded forwardly from the phantom to the solid position in FIG. 4.

In the operation of the present bridge-painting apparatus, it is envisioned that the motor vehicle 20 may e guided by reference to certain fixed features on the bridge 22. For example, in FIG. 1 the bridge 22 may be provided with a curb 102 or a railing or other abutment means 104 which permit a sensing means indicated generally at in FIG. 13 to function. The motor vehicle 20 may have a sensing means 110 mounted on either side of the vehicle although only one of the sensing means is actually in operation at any given time. I

The operation of the present invention contemplates that the motor vehicle 20 may be completely unattended. In this connection and referring to FIG. 13, the motor vehicle has a main transmission 112 from which one or more power takeoffs may be made such as by a hydraulic pump 114 and an air compressor 116. An auxiliary transmission is employed by means of which the motor vehicle may be driven automatically with a remote control 118 being used to control the auxiliary transmission. The auxiliary transmission 120 m may have one or more power takeoffs, for example, hydraulic motor 122. In one embodiment of the invention, the speed of the remotely controlled truck was variable from 1 inch per hour to 21 feet per minute.

Reference to FIG. 16 shows the sensing means 1 10 which as has already been noted may be attached to either side of the vehicle whereby the vehicle may operate on any suitable abutment means on the bridge being painted, inspected, stripped or otherwise being worked on. The sensing means 110 is shown to comprise a switch means 124, which is provided with a bridge abutment engaging roller 126. Switch means 124 of the sensing means 110 seeks a central position whereby execssive hunting corrections are prevented. The amount of correction is proportional to the quantum of the force that necessitates the correction. A pitman 128 is adjustably secured and locked at one end to the switch 124 and is also locked at an adjustable length at its other end to a rod 130. The free end of rod 130 is provided with a swivel connection at I32. A swivel connection is made at one end of rod 134, intermediate the rod 130, and the other end of rod 134 is swiveled at 138 to an actuating rod 140. One swivel connection is provided at 142 for actuating rod and a further swivel connection is made at 144 on collar 146 for the wheel 148 of the truck which is being guided. A tie rod 152 interconnects the wheels 148 and is provided with swivel connections at 150. It should be noted that in addition to applying a force to he actuating rod 140 it may alternatively be desirable to apply the travel correction force to the tie rod 152.

Reference to FIG. 17, shows a schematic diagram of an automatic hydraulic power steering circuit generally designated at for use in connection with the present invention. While it is convenient to use a hydraulic circuit, electric or pneumatic circuits may be employed alternatively. The bridge engaging rollers 126 of the sensing means 110 in FIG. 16 provide an input to a manually controlled valve 162 which connects with a piston and cylinder assembly 164. An output of the piston and cylinder assembly 164 communicates with a manually controlled selector valve 166 and an electrically controlled valve 168. Numeral 170 designates a torque generator used for highway steering. The position of electrically controlled valve 172 determines when torque generator 170 is employed and when engine 174 is inserted into the .system to drive the bridge-painting apparatus under remote control. Engine 174 has associated with it a pump 176, a strainer 178, a check valve 180 and relief valve 182. Overload relief valve means are indicated at 184 and a check valve means at 186.

In the embodiment shown in FIG. 18, another means is provided for tilting the work platform afforded by the extensible scaffold mans 38. In this embodiment, a pair of hydraulic cylinders 118 provide the interconnection between the two outermost vertical members 190, 192 of the reinforcing frame means 36 and the tray 40 of extensible scaffold means 38. A pin connection is provided at 194 at the base of boom 34 to connect it to tray 40. Thus, upon actuation of hydraulic cylinder 188, the tray is lowered up to l fiinches which by virtue of the pivotal connection at 194 and the lever arms involved results in a substantial raising of the free end of the extensible members 42 held by tray 40. Thus it will be seen that means independent of the position of the boom are provided for tilting the extensible scaffold means 38 in a vertical plane.

' The operation of the folding sequence of the bridge-painting apparatus will now be given. With the bridge-painting apparatus as shown in FIG. 2, the boom 34 is extended over the side 35 of the bridge 22 to be painted and the operators may walk upon the platform provided by the extensible scaffold means 38 comprising the main scaffold 40, and one or more extensible scaffold members 42. Control of all the folding equipment as well as the driving means for the motor vehicle may be controlled at control box 118, for example. Initially, the extensible scaffold 42 is telescoped within the main scaffold and may extend rearwardly such as is shown in phantom at 42 at which point the boom 34 is rotated together with its associated reinforcing frame 36 and the main scaffold 40. Rotation of these elements is undertaken so as to bring he attaching means 37 into alignment with the split 74 in the split collars 72 of the split collar construction 70. Thereafter, the boom and its associated equipment is fully elevated with the attaching means 37 passing through the split 74 in the split collar 72, as illustrated in FIGS. 10 and 3, for example. The counterweight means 44 is also controlled from the remote control position 118 or alternatively, may be controlled from the c cabin of the truck 20. After the boom 34 has been elevated, the turntable 26 is rotated so as to bring the counterweight means 44 to the front of the truck bed 28 and the boom-holding frame 32 to the rear of the truck with this position being indicated in FIG. 4. The knuckle joint 100 of the boom 34 is then broken whereby the boom and its associated reinforcing frame 36 are folded forwardly as indicated in the solid'line position in FIG. 4. The extensible scaffold means 38 may then be rotated 90 and then extensible scaffold members 42 moved forwardly of the truck bed 28. The arrangement of the counterweight means 44 is such that he extensible scaffold members 42 may be inserted between he legs 48 but beneath the counterweight 46.

While it is preferred to rotate the turntable 26 clockwise, as viewed in top plan view, and to lay the boom forwardly toward the cabin of the motor vehicle, it is possible to turn the turntable 26 counterclockwise to lay the boom own in a direction away from the cabin of the motor vehicle toward the plane of the truck bed. It is preferred to have the cabin of the motor vehicle offset with respect to the centerline of the truck whereby the boom and the extensible scaffold means may extend alongside the cabin of the motor vehicle.

It is thought that the invention andmany of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention of sacrificing all of its material advantages, the forms hereinbefore described being merely preferred embodiments thereof.

What is claimed is:

I. In a bridge-painting apparatus of the type having a boom, means for extending said boom over a side of a bridge to be painted, and means for rasing and lowering said boom, the improvement comprising a split collar construction through which said boom may be raised and lowered whereby said apparatus may be collapsed without dismantling any of said ap-j paratus.

2. A bridge-painting apparatus as defined in claim 1 including a. reinforcing framemeans carried by said boom,

b. attaching means for securing said reinforcing frame means to said boom,

c. and means to rotate said boom so as to obtain vertical alignment of said attaching means with the split in said split collar construction.

3. A bridge-painting apparatus as defined in claim 1 including extensible scaffold means carried by said boom and said frame reinforcing means.

4. A bridge-painting apparatus as defined in claim 3 including a motor vehicle on which said bridge painting apparatus is mounted.

5. A bridge-painting apparatus as defined in claim 4 including remote control means for controlling said motor vehicle and said bridge painting apparatus.

6. A bridge-painting apparatus as defined in claim 5 wherein said remote control-means is operable from said extensible scaffold means.

7. A bridge-painting apparatus as defined in claim 4 including sensing means mounted on said motor vehicle for sensing abutment means on said bridge whereby said vehicle may be driven continuously and automatically while said apparatus is used in painting said bridge.

8. A bridge-painting apparatus as defined in claim 7 includa. reinforcing frame means carried by said boom,

b. attaching means for securing said frame-reinforcing means to said boom,

c. and means to rotate said boom so as to obtain vertical alignment of said attaching means with the split in said split collar construction.

9. A bridge-painting apparatus as defined in claim 1 including means for varying the angle that said boom makes with the vertical when said boom extends over a side of said bridge.

10. A bridge-painting apparatus as defined in claim I wherein said boom has extensible scaffold means carried thereby and including counterweight means to balance said means for extending said boom over a side of said bridge, said boom and said extensible scaffold means.

11. A bridge-painting apparatus as defined in claim 10 including means independent of the position of said boom for tilting said extensible scaffold means in a vertical plane.

12. A bridge-painting apparatus as defined in claim 1 wherein said split collar construction is carried by said means for extending said boom over a side of the bridge to be painted.

13. A portable bridge-painting apparatus comprising:

a. a truck bed,

b. a turntable mounted for rotation on said truck bed,

c. a boom-holding frame mounted on said turntable,

d. a boom held in said boom-holding frame,

e. extensible scaffold means carried by said boom,

f. and a split collar construction held by said boom holding frame and through which said boom may be raised and lowered without dismantling any of said bridge painting apparatus.

14. A portable bridge-painting apparatus as defined in claim 13 including a reinforcing frame construction affixed to said boom and to which said extensible scaffold means is attached.

15. A portable bridge-painting construction as defined in claim 13 wherein said boom-holding frame has a fixed part and a movable part with said boom being held by said movable part.

16. A portable bridge-painting apparatus as defined in claim 15 wherein said movable part of said boom-holding frame is telescopically received in said fixed part of said boom-holding frame.

17. A portable bridge-painting apparatus as defined in claim 16 wherein hydraulic cylinder means is used to move said movable part of said boom-holding frame.

18. A portable bridge painting apparatus comprising:

a. a truck bed,

b. a turntable mounted for rotation on said truck bed,

c. a boom-holding frame mounted on said turntable,

d. a boom held in said boom-holding frame,

e. extensible scaffold means carried by said boom,

f. and means to tilt said boom-holding frame with respect to the plane of said truck bed.

19. A portable bridge-painting apparatus as defined in claim 13 including means independent of the position of said boom for tilting said extensible scaffold means in a vertical plane.

20. A portable bridge-painting apparatus as defined in claim 13, wherein said boom is held by said boom-holding frame from one side of saidplatform, and said platform has counterweight means mounted on the opposite side thereof.

21. A portable bridge-painting apparatus as defined in claim 20 including means to position said counterweight means outwardly of said opposite side of said platform.

22. A portable bridge-painting apparatus as defined in claim 13 including means to vary in a substantially horizontal plane the angle that said extensible scaffold mans makes with said boom to compensate for skewed bridge holding piers.

23. A portable bridgepainting apparatus as defined in claim 13 wherein said boom is articulated.

24. A portable bridge-painting apparatus as defined in claim 13 including remote control means on said extensible scaffold means by which the extension and contraction of said extensible scaffold means and the position of said boom is controlled, whereby said apparatus is moved to and from a stacked position on said truck bed to a bridge-painting position in which said boom is vertically suspended over the side of the bridge to be painted and said extensible scaffold means extends beneath the bridge to be painted.

25. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus and placing said extensible scaffold means on the bed of a motor vehicle, said bridge-painting apparatus including a truck bed, a turntable mounted for rotation on said truck bed, a boom-holding frame mounted on said turntable, a boom held in said boom-holding frame, a split collar construction held by said boom-holding frame and through which said boom is vertically reciprocable, said extensible scaffold means being carried by said boom, reinforcing frame means carried by said boom, an attaching means for securing said reinforcing frame means to said boom, comprising the steps of:

a. rotating said boom and said reinforcing frame to align said attaching means of said reinforcing frame with the split in said split collar construction,

b. elevating said boom, said reinforcing frame and said extensible scaffold means by passing said attaching means through the split of said split collar construction,

c. and rotating said turntable on said truck bed whereby said bridge-painting apparatus may be transported over a highway.

26. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus as defined in claim 25 including the additional step of collapsing said boom and laying it down in a direction toward the plane of said truck bed.

27. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus as defined in claim 25 including the additional step of extending said extensible scaffold means in a direction toward the plane of said truck bed.

28. A method of folding and unfolding an extensible scat fold means for a bridge-painting apparatus as defined in claim 25 wherein said boom-holding frame is mounted on one side of said turntable and counterweight means are mounted on an opposite side of said turntable, said counterweight means being movable between an extended position and a nonextended position, and said method further includes the step of positioning said counterweight means in its nonextended position when said bridge-painting apparatus is in position to be transported over a highway. 

1. In a bridge-painting apparatus of the type having a boom, means for extending said boom over a side of a bridge to be painted, and means for raising and lowering said boom, the improvement comprising a split collar construction through which said boom may be raised and lowered whereby said apparatus may be collapsed without dismantling any of said apparatus.
 2. A bridge-painting apparatus as defined in claim 1 including a. reinforcing frame means carried by said boom, b. attaching means for securing said reinforcing frame means to said boom, c. and means to rotate said boom so as to obtain vertical alignment of said attaching means with the split in said split collaR construction.
 3. A bridge-painting apparatus as defined in claim 1 including extensible scaffold means carried by said boom and said frame reinforcing means.
 4. A bridge-painting apparatus as defined in claim 3 including a motor vehicle on which said bridge painting apparatus is mounted.
 5. A bridge-painting apparatus as defined in claim 4 including remote control means for controlling said motor vehicle and said bridge painting apparatus.
 6. A bridge-painting apparatus as defined in claim 5 wherein said remote control means is operable from said extensible scaffold means.
 7. A bridge-painting apparatus as defined in claim 4 including sensing means mounted on said motor vehicle for sensing abutment means on said bridge whereby said vehicle may be driven continuously and automatically while said apparatus is used in painting said bridge.
 8. A bridge-painting apparatus as defined in claim 7 including a. reinforcing frame means carried by said boom, b. attaching means for securing said frame-reinforcing means to said boom, c. and means to rotate said boom so as to obtain vertical alignment of said attaching means with the split in said split collar construction.
 9. A bridge-painting apparatus as defined in claim 1 including means for varying the angle that said boom makes with the vertical when said boom extends over a side of said bridge.
 10. A bridge-painting apparatus as defined in claim 1 wherein said boom has extensible scaffold means carried thereby and including counterweight means to balance said means for extending said boom over a side of said bridge, said boom and said extensible scaffold means.
 11. A bridge-painting apparatus as defined in claim 10 including means independent of the position of said boom for tilting said extensible scaffold means in a vertical plane.
 12. A bridge-painting apparatus as defined in claim 1 wherein said split collar construction is carried by said means for extending said boom over a side of the bridge to be painted.
 13. A portable bridge-painting apparatus comprising: a. a truck bed, b. a turntable mounted for rotation on said truck bed, c. a boom-holding frame mounted on said turntable, d. a boom held in said boom-holding frame, e. extensible scaffold means carried by said boom, f. and a split collar construction held by said boom holding frame and through which said boom may be raised and lowered without dismantling any of said bridge painting apparatus.
 14. A portable bridge-painting apparatus as defined in claim 13 including a reinforcing frame construction affixed to said boom and to which said extensible scaffold means is attached.
 15. A portable bridge-painting construction as defined in claim 13 wherein said boom-holding frame has a fixed part and a movable part with said boom being held by said movable part.
 16. A portable bridge-painting apparatus as defined in claim 15 wherein said movable part of said boom-holding frame is telescopically received in said fixed part of said boom-holding frame.
 17. A portable bridge-painting apparatus as defined in claim 16 wherein hydraulic cylinder means is used to move said movable part of said boom-holding frame.
 18. A portable bridge painting apparatus comprising: a. a truck bed, b. a turntable mounted for rotation on said truck bed, c. a boom-holding frame mounted on said turntable, d. a boom held in said boom-holding frame, e. extensible scaffold means carried by said boom, f. and means to tilt said boom-holding frame with respect to the plane of said truck bed.
 19. A portable bridge-painting apparatus as defined in claim 13 including means independent of the position of said boom for tilting said extensible scaffold means in a vertical plane.
 20. A portable bridge-painting apparatus as defined in claim 13, wherein said boom is held by said boom-holding frame from one side of said platform, and said platform has counterweight means mounted on the oppOsite side thereof.
 21. A portable bridge-painting apparatus as defined in claim 20 including means to position said counterweight means outwardly of said opposite side of said platform.
 22. A portable bridge-painting apparatus as defined in claim 13 including means to vary in a substantially horizontal plane the angle that said extensible scaffold means makes with said boom to compensate for skewed bridge holding piers.
 23. A portable bridge-painting apparatus as defined in claim 13 wherein said boom is articulated.
 24. A portable bridge-painting apparatus as defined in claim 13 including remote control means on said extensible scaffold means by which the extension and contraction of said extensible scaffold means and the position of said boom is controlled, whereby said apparatus is moved to and from a stacked position on said truck bed to a bridge-painting position in which said boom is vertically suspended over the side of the bridge to be painted and said extensible scaffold means extends beneath the bridge to be painted.
 25. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus and placing said extensible scaffold means on the bed of a motor vehicle, said bridge-painting apparatus including a truck bed, a turntable mounted for rotation on said truck bed, a boom-holding frame mounted on said turntable, a boom held in said boom-holding frame, a split collar construction held by said boom-holding frame and through which said boom is vertically reciprocable, said extensible scaffold means being carried by said boom, reinforcing frame means carried by said boom, and attaching means for securing said reinforcing frame means to said boom, comprising the steps of: a. rotating said boom and said reinforcing frame to align said attaching means of said reinforcing frame with the split in said split collar construction, b. elevating said boom, said reinforcing frame and said extensible scaffold means by passing said attaching means through the split of said split collar construction, c. and rotating said turntable on said truck bed whereby said bridge-painting apparatus may be transported over a highway.
 26. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus as defined in claim 25 including the additional step of collapsing said boom and laying it down in a direction toward the plane of said truck bed.
 27. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus as defined in claim 25 including the additional step of extending said extensible scaffold means in a direction toward the plane of said truck bed.
 28. A method of folding and unfolding an extensible scaffold means for a bridge-painting apparatus as defined in claim 25 wherein said boom-holding frame is mounted on one side of said turntable and counterweight means are mounted on an opposite side of said turntable, said counterweight means being movable between an extended position and a nonextended position, and said method further includes the step of positioning said counterweight means in its nonextended position when said bridge-painting apparatus is in position to be transported over a highway. 